I've had a look at the search page, and didn't find anything useful...
I'm trying to write a program to generate PNG images from a bitmap, but i can't get it working. It seems that zlib is compressing my 110 byte bitmap data down to 12 bytes, surely thats not right? My input image looks like this:
And heres the code for the compression:
// Setup compression stream //
ZeroMemory(&theStream,sizeof(theStream));
deflateInit(&theStream,9);
theStream.next_in = pbyInput;
theStream.avail_in = (bmpInfo.bmWidth+1)*bmpInfo.bmHeight;
theStream.total_in = 0;
theStream.next_out = pbyData;
theStream.avail_out = dwLen;
theStream.total_out = 0;
// Compress Chunk //
if(deflate(&theStream,Z_FINISH) != Z_STREAM_END) goto lblError;
delete[] pbyInput;
pbyInput = NULL;
// Write Chunk//
// Snipped - just writes theStream.total_out bytes to file //
delete[] pbyData;
pbyData = NULL;
deflateEnd(&theStream);
I get my image data from GetObject() on a DIB section, and i copy it into pbyInput, adding a 0 byte at the start of each scanline (for the filter type), so in total my input data is 110 bytes.
Any help would be great.
[edited by - Evil Bill on April 19, 2003 10:41:03 AM]
[edited by - Evil Bill on April 19, 2003 10:41:30 AM]
[edited by - Evil Bill on April 19, 2003 11:45:51 AM]
. I tried inflating the data after i deflated it and it comes out the same as it went in, so its compressing it ok.
